Catalyst and method for alkli-free purification of oil raw materials from mercaptans

ABSTRACT

A catalyst for alkali-free purification of oil raw material, consisting of a metalocomplex selected from the group consisting of a solid metalocomplex and a liquid metalocomplex with a general formula (Cu II Cl) 2 O(L 1 ) 2-4 (L 2 ) 1-4 , where L 1  is amino alcohol L 2  is acetonitrol or single atom alcohol.

BACKGROUND OF THE INVENTION

The present invention relates to catalysts for purification of gaseouscondensate and oil fractions from mercaptans and can be used inoil-processing and in petrochemical industry.

Usually oxidation of mercaptans is performed by oxygen or air at room orelevated temperature in the presence of homogenous or heterogeneouscatalyst based on a transitional metal:

2RSH+½0₂→RSSR+H₂0

Mercaptans are extracted from organic phase by strongly alkali aqueoussolutions, in which at elevated temperature and pressure catalyticaloxidation of mercaptans takes place, and as a catalyst salts from metalsof alternating valency (Fe, Co, Ni, V, Mn, Cr) in the form of simple orcomplex compositions, more often phatocyanites (as disclosed for examplein European patent no. 394571, German patent 3008284 and others). Thecatalysts of this type provide sufficiently complete removal ofmercaptans. Their common disadvantage is not sufficient availability andhigh cost of phatocyanites, which leads to making the process ofpurification expensive. Moreover, the necessity to conduct the processin strongly-alkli medium leads to a significant corrosion of equipmentand worsening of the properties of oil pipelines.

It is known that phtalocyanines in catalytical compositions can bereplaced with other compounds of transitional metals.

A catalyst are known based on metallo-organic derivatives of metals ofVIA, VIIA, and VIII groups with general formula Me_(a)(R)x(CO)y where Ris aromatic ligand, for example benzol or its alkyl derivatives,antrazen, benzpirin, phenanthren (U.S. Pat. No. 3,053,756).Disadvantages of such catalysts include their low stability, high costand toxicity.

A catalyst for oxidating demercaptanization of carbohydrates is knownwhich is a helate complex of a transitional metal with bi, tri, or tetradentant ligand, containing at least one amide group (French patent2,573,087). In particular, replaced 2-(alkyl(aryl,alkylary))-aminocarboxypyriditines and others even more complicatedcompounds are utilized. As a metal it can be Co, Fe, Cu, Ni, Mn. Thedisadvantage is a low stability of the catalyst and use for itsmanufacture of expensive and scarse components.

Also, catalysts of oxidating demercaptnization are known-complexes ofcopper with tetracyantiophenol and tetracyandentin (French patent2591610). These catalysts provide high degree of purification, but theirpractical use is questionable because their very high cost and scarseavailability of the components.

A method of oxidative demercaptinization are known which is performed byoxidation of mercaptans with oxygen of air in presence of helatecomplexes of a transitional metal (Co, Fe, Cu, Ni, Mn) with polydentanligand from the class of amides, in particular fromaminocarboxyperidines (French patent 2573087). The main disadvantage ofthe method with the use of this catalyst is high cost of its components.

A heterogeneous catalyst is described, based on complexes of copper withamino derivatives (aminoalcohols, aminoacids, amines) applied on amineral carrier or activated coal (European patent 996500). Thedisadvantage of this catalyst is a low content of active phase on thesurface of the carrier, which inevitably leads to a significantconsumption of the heterogeneous catalyst.

The closest solution to the present invention is disclosed in U.S.patent no. In accordance with this patent, a catalyst of alkali-freepurification of oil fractions from mercatans is proposed, which containsa copper oxide, a complex of copper with nitrogen-containing compound ofamines, aminoalcohols, aminoacids, or amids and an inert carrier. Thedisadvantage of this method is a complex technology for producingcatalyst and a high consumption of the carrier, which makes the catalystquite expensive.

SUMMARY OF THE INVENTION

The objective of this invention is to reduce the cost of a catalyticcomposition by eliminating utilization of a mineral carrier and usingsolid or liquid complexes which contain a copper chloride, aminoalcoholand acetonitryl or single-atom alcohol selected from isopraponal,butanol, isobutanol, and pentanol.

In accordance with the invention a catalyst is proposed for alkali-freepurification of oil raw materials, consisting of a metalocomplexselected from the group consisting of a solid metalocomplex and a liquidmetalocomplex with a general formula (Cu^(II)Cl)₂O(L₁)₂₋₄(L₂)₁₋₄, whereL₁ is amino alcohol, L₂ is acetonitryl or single atom alcohol.

In accordance with a further feature of the invention as theaminoalcohol a compound of a general formula N(R₁)(R₂)(R₃)(OH)₁₋₃ isutilized, where R₁=C₂H₄, R₂=H, C₂=H, C₂H₄, C₂H₅, R₃=H, C₂H₄,C_(n)H_(2n+1), where n=2-17.

In accordance with still a further feature of the invention as a singleatom alcohol a substance selected from the group consisting ofisopropanol, butanol, isobutanol and pentanol is utilized.

The novel features which are considered as characteristic for thepresent invention are set forth in particular in the appended claims.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention resides, in a catalyst for purification of oil rawmaterial with the use of a metalocomplex of general formula(Cu^(II)Cl)₂O(L₁)₂₋₄(L₂)₁₋₄, wherein L₁ is amino alcohol of the generalformula N(R₁)(R₂)(R₃)(OH)₁₋₃, wherein R₁=C₂H₄, R₂=H, C₂H₄, C₂H₅, C₂H₅,R₃=H, C₂H₄, C_(n)H_(2n+1), wherein n=2-17, L₂ is acetonitryl or theabove mentioned alcohol.

The metal complex is synthesized in acetonitryl or alcohol starting fromCuCl and aminalcohol at 45-50° C. in air.

The catalyst actively oxidizes mercaptans and hydrogen sulfide withoxygen of air at temperature 22-120° C. and at atmospheric pressure.

The objective of the present invention can not be achieved if at leastone of the above mentioned components of catalytic complex are not usedor the conditions of synthesis are not complied with, for example:

-   -   If instead of copper chloride CuCl2 is used or another salt is        used (nitrate, sulfate, stearate, etc.)    -   If amino alcohol is not used, the complex is not active;    -   If as a solvent acetylnitryl or alcohol is not used, the        activity of catalyst is reduced. For example, if acetylnitryl is        replaced with chloroform, the activity of catalyst is reduced        three times.

Therefore, the present invention resides in a catalyst of oxidatingalkali-free demercaptanization of oil, gas condensate or oil fractionbased on a metalocomplex of the above mentioned composition.

The present invention is illustrated by the following examples.

Example 1 Producing of Solid Metalocomplex

100 ml of saturated solution of CuCl in acetonitryl (the solutioncontains 8 g of CuCl) is introduced into a flat-bottom container of 200ml at room temperature, and heated to 45-50° C. With continuous steeringby a magnetic stirrer, slowly (in 30-40 min) from a peeped 20 ml ofsolution of monoethanolamine in acetonenitryl is introduced into thecontainer (solution is prepared by mixing of 17 ml of monoethanolamineand 100 ml of acetonitryl).

The precipitated substance of blue-green color is separated from amother solution on a filter, dried on air and then in a drying cabinetat 100-105° C. The obtained dry complex contains 9.2-9.5 g. Beforetesting the solid catalyst is comminuted in a porcelain dish. This way,catalyst A is produced. Catalyst B and C were produced analogously, butinstead of monoethanolamine, dimethylamineethanol ethanol and threeethanolamine were utilized

Example 2 Production of Liquid Metalocomplex D-F

20 ml of aminoalcohol Atmer 163 which is a mixture of isomers with thecomposition RN(CH₂CH₂OH)₂, where R=C_(n)H_(2n+1) n=16-17 and 20 mlisobutanol is introduced into a flat bottom container. During mixing andheating to 45-50° C. in air, slowly 10 g CuCl is added. As a result, adark-brown dense liquid is produced. Before testing, the obtained liquidcomplex D is dissolved in an excessive quantity of isobutanol toconcentration Cu(II) 1-1.5%. Catalyst E and F are produced analogously,but instead of isobutanol, butanol and isopropanol were added.

Example 3 Production of Liquid Metalocomplex H

20 ml of triethanolamine and 10 ml of pentanol are introduced into aflat bottom container. During heating and mixing to 50-55° C., slowly 12g CuCl is added. As a result, a dark-green dense liquid is formed.Before testing the obtained liquid complex H is dissolved in anexcessive quantity of pentanol to concentration Cu (II) 1.15%.

Example 4 Purification of Kerosene on Solid Catalyst

A reactor with a magnetic stirrer is utilized, which is formed as afour-neck flat-bottom container with volume of 350 ml, composed OFmolybdenum glass and provided with swdlwfmROE, a system of air andoxygen supply and a glass pipe for taking samples A kerosene fractionwith a content of mercaptide sulfer 80 ppm, a batch of catalyst A (ratioof raw material to catalyst is 62000 ml/g) and Teflon magnetic stirrerwere are introduced. The reaction time was four hours. During this timethe content of sulfur was reduced to 30 ppm. The samples were taken withinterval of 0.5 hour.

Example 5 Purification of Fuel Oil of Gas Condensate on Solid Catalyst

The process was conducted as in Example 2 but instead of kerosene, fueloil from gas condensate was used, which contained 1200 ppm of mercaptidesulfur (a gas condensate was used which was distilled in interval56-354° C. with density 0.77 g/cm³ and content of moisture 0.04% mass).The ratio of raw material to catalyst was 7000 ml/g. The temperature ofreaction was 120° C. In 1 hour the concentration of sulfur was reducedto 590 ppm.

TABLE 1 Test results of purification of kerosene and gas condensate onsolid catalyst. Ratio of raw material: Content of Mercaptan PetroleumCatalytical sulfur, ppm product to Solution Temperature In Raw After theCatalyst be Purified (ml/MI ° C. Material Reaction A Kerosene 120000 7080  4 hours-20 A Kerosene 62000 22 80 10 hours-40 A Fuel Oil 7000 451200 10 hours-800 B Kerosene 62000 70 80  4 hours-25 B Fuel Oil 7000 1201200  2 hours-450 C Kerosene 100000 70 80  4 hours-25

Example 6 Purification of Fuel Oil from Gas Condensate with the Use ofLiquid Catalyst

Liquid complex D is dissolved in an excessive quantity of isobutanol toconcentration Cu (II) 1%. Into the reactor described in Example 4, fueloil was introduced with content of mercaptide sulfur 1200 ppm. The ratioof raw material to solution of catalyst 2000 ml/ml. Temperature ofreaction was 100° C. In two hours the concentration of sulfur reduced to550 ppm.

With increase of concentration of liquid complex in isobutanol to Cu(II) 1.5%, with the same conditions in 2 hours the concentration ofsulfur reduced to 450 ppm.

TABLE 2 Test results of purification of kerosene and gas condensate withthe use of liquid metalocomplex. Ratio of raw material: Content ofMercaptan Petroleum Catalytical sulfur, ppm product to SolutionTemperature In Raw After the Catalyst be Purified (ml/MI ° C. MaterialReaction D Kerosene 100000 70 80 3 hours-20 E Kerosene 100000 22 80 3hours-40 E Fuel Oil 7000 120 1200 4 hours-300 F Fuel Oil 7000 70 1200 4hours-800 F Fuel Oil 4000 120 1200 2 hours-200 G Fuel Oil 7000 70 1200 4hours-750 H Fuel Oil 7000 120 1200 4 hours-720 D Raw Oil ** 4000 70 23004 hours-1600 F Raw Oil 4000 22 2300 4 hours-1950 *Catalytic solutioncontains 1% Cu²⁺ **Oil with density of 0.80 g/cm³ with the outputfraction 28-360° C. 88%, content of paraffin hydrocarbon 65%,naphten-26% was used.

Examples 7-8 show that it is not possible to keep the objects of thepresent invention if parameters of catalyst deviate from the parametersin accordance with the present invention.

Example 7

Synthesis of the complex is performed as in Example 1 but insteadacetonitryl, chloroform is utilized. During with the process ofpurification of kerosene in accordance with FIG. 2, the content ofmercaptan sulfur is reduced to 60 ppm.

Example 8

Synthesis of the complex is performed as in Example 1, but the reactionsolution is not heated. When the purification is performed with Example2, the content of mercaptide sulfur is reduced to 40 ppm.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofsubstances and methods differing from the type described above.

While the invention has been illustrated and described as embodied incatalyst and method for alkali-free purification of oil raw materialfrom mercaptans, it is not intended to be limited to the details shown,since various modifications and structural changes may be made withoutdeparting in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, be applying current knowledge,readily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this invention.

1. A catalyst for alkali-free purification of oil raw materials,consisting of a metalocomplex selected from the group consisting of asolid metalocomplex and a liquid metalocomplex with a general formula(Cu^(II)Cl)₂O(L₁)₂₋₄(L₂)₁₋₄, where L₁ is amino alcohol, L₂ isacetonitryl or single atom alcohol.
 2. A catalyst as defined in claim 1,wherein as the aminoalcohol a compound of a general formulaN(R₁)(R₂)(R₃)(OH)₁₋₃ is utilized, where R₁=C₂H₄, R₂=H, C₂=H, C₂H₄, C₂H₅,R₃=H, C₂H₄, C_(n)H_(2n+1), where n=2-17.
 3. A catalyst as defined inclaim 1, wherein as the single atom alcohol a substance selected fromthe group consisting of isopropanol, butanol, isobutanol and pentanol isutilized.
 4. A method of purification of pure fractions and gascondensate from mercaptans by processing of oil raw material with air inthe presence of a catalyst, comprising the steps of missing a catalystof for alkali-free purification of oil raw materials, consisting of ametalocomplex selected from the group consisting of a solidmetalocomplex and a liquid metalocomplex with a general formula(Cu^(II)Cl)₂O(L₁)₂₋₄(L₂)₁₋₄, where L₁ is amino alcohol, L₂ isacetonitryl or single atom alcohol.
 5. A method as defined in claim 4,wherein as the a compound of a general formula N(R₁)(R₂)(R₃)(OH)₁₋₃ isutilized, where R₁=C₂H₄, R₂=H, C₂=H, C₂H₄, C₂H₅, R₃=H, C₂H₄,C_(n)H_(2n+1), where n=2-17
 6. A method as defined in claim 4, whereinas the single atom alcohol a substance selected from the groupconsisting of isopropanol, butanol, isobutanol and pentanol is utilized.